JRX Pro ebay find, runner rebuild

[RogueIV]

Friday I finally got my new project in. The previous owner must have really liked Miller.







Despite the mismatched screws and some maintenance neglect and some incorrect parts like shocks and wheel it was in pretty good shape. Also pretty nice original Trinity Monster stock motor.



I started tearing into it yesterday, Lot of play in the front suspension, diff wasn't working properly and the drive pins in the axles were floppy, pretty typical stuff.

Pulled apart the transmission first to find what I suspected, a melted diff.


Ended up rebuilding the diff with regular plastic diff halves and a thorp aluminum center diff gear. would have used the entire thorp diff but male diff half i have was damaged. The screws were all mismatched int he transmission and I feared that the motorplate was stripped out, thankfully I was proven wrong and installed some fresh hardware from Sebulatech.


I had a "profiled" purple rear spur gear that I decided to throw on to give it a little more color. Also replaced the JRX2 rear pivot block with a proper H arm style pivot block, this one a #3 for 5degrees of toe in and 4 degrees of antisquat. I would have prefered a #4 but I can't seem to find one in my stash as of right now.



I actually have an old A&L slipper assembly that I may use on this build later on. I need to get a few missing parts for it later from Factory Works.

Drive pins on this thing were pretty worn out so I replaced those. as well. It's kinda amazing how much the metal was worn away being in contact with plastic parts.


I had a bunch of losi shock parts I assembled into the proper length shocks for this buggy. Sadly I didn't have a matched set of silver bodies so the newer style rears will have to work for this one. I also noted that the rear tower did not have it's spacer, so I quickly measured up and 3d printed one, this one 7mm thick and not an exact replica asi enclosed the bottom screw holes. I'm not sure how thick the original was as my LXT is still out on loan.



The rear shock tower is missing the body mount so i placed an order for some new Carbon towers from Vintage RC. The car has some Metric screws, but I decided to just keep them that way, M3 screws are probably better than 4-40s anyway. Tossed on a old set of Proline wheels just so it can roll. not sure my plans on wheels/tires yet, I might make adapters for modern 12mm wheels at some point. Here's where we are for now.



I put CA in all the loose bulkhead holes and reamed them back out to 1/8" to get rid of the slop. I do have original JRX2 and JRX Pro SE front arms but I think I'll keep these Andy's ones on since I plan on running this car a bit.


I also have a complete 5 link setup as well, If I end up finding a composite chassis for my LXT I'll pull the JRX2 chassis it's currently using aside for switching this car back and forth, or maybe making dedicated JRX2. Anyway more to come.

[RogueIV]

Few small updates. I ended up purchasing a ebay lot earlier which includes a full LXT, some XX and XXX parts and chassis and what I hope is a JRX2 chassis as well as a load of parts so excited to see that come in this weekend.

I ended up getting my carbon towers from Vintage R/C. I bought all 3 JRX flavors: JRX2, Pro and Pro SE. they look sweet and are thicker than the original by a bit. Pro version gets rid of the unusable camber link holes on the rear as well (why did Losi put those there??)













Noticed a LOT of bind on the front suspension arms seems like these Andy's arms are made for a different buggy and the pin holes are undersized and the shock positions are further out. I just put the original JRX2 arms back on. If anyone has any insight on what these Andy's arms actually goto I'm all ears.







I also found a Pink Peak Power stock motor in my stash and decided to bolt that up to the chassis.

In the future I'm going to modify one of my existing 3d printed battery adapter designs I did for my XXX-T so i can use my shorty Lipos on the JRX platform.

[Chewbacca]

Not really sure, those Andy's arms could be for the RC10.

[RogueIV]

She's a runner now. The electronics layout isn't pretty, mostly becuase I have the battery adapter cable and lipo voltage monitor that i use to run on my older electronics. The Futaba ESC is pretty damn nice. need to do some swapping of tires and such before I run it on a track. I found that JC Racing makes JRX2 wheels that are 2.2 so I'm definitely going to try to source a couple sets of those might do an upscaled version of my Pro logo wheels wheels I did for the mini later on for this. Didn't have to redo the battery hold down adapter, I just moved the Pure Tech strap forward more since where it was mounted originally the holes were kinda messed up. Still need a new body, wing, wing tubes, some hardware and replace some ballcups that have excessive slop (but still not as bad as the Mini JRX2 out of the box lol) but overall I'm fairly happy with it as a runner, although it is a bit on the uglier side.

[BattleTrak]

Looking good and not too ugly at all..you’ve seen my jrxt build, right? The only thing that looks off to me is the 2.5” pink front springs..too long unless you cut off 3 coils like the Jammin steering enhancement kit recommends.

[RogueIV]

Looking good and not too ugly at all..you’ve seen my jrxt build, right? The only thing that looks off to me is the 2.5” pink front springs..too long unless you cut off 3 coils like the Jammin steering enhancement kit recommends.

Thanks! Yeah concours wasn't my intention with this anyway hahha.

The jammin kit was for the Pro SE, no? This is a regular Pro that has the .9" travel front shocks, same as the trucks. The springs are a bit long for my prefered ride height but not 3 coils too long. Would definitely be an issue on the shorter .6 travel shocks. I might be trying a bunch of different spring rates on this anyway since my home track is high grip smooth carpet and not dirt where these were devolped on. I also will likely build up a Pro SE buggy in the future.

[BattleTrak]

Yeah that’s true! Ha.. Typically the .9 shocks use a 2” spring. 1.5” on .6, 2.5-2.75” on 1.2 rears. I’m almost done with my ProSE build..nice buggy buy the JrxPro is my favorite.

[RogueIV]

Yeah that’s true! Ha.. Typically the .9 shocks use a 2” spring. 1.5” on .6, 2.5-2.75” on 1.2 rears. I’m almost done with my ProSE build..nice buggy buy the JrxPro is my favorite.

This is the first Pro I've owned. Pro SE was the first hobby grade i owned but that was long since sold but been wanting to get another. I blame the release of the Mini JRX2 for sparking my want for all the jrx based buggies. I wish i could get engineering notes on the reasons behind the changes losi did over the models.

[RogueIV]

Not much to report.I replaced the super loose rear ballcups with some I had in an old pit box and drove it for a bit at the local indoor carpet offroad track.





It definitely needs some tweaking but handled OK for it's initial setup, lots of fun body roll but not too much traction rolling except for one tight left hand turn, which i found out was probably due to left hand shock eyelet was one of the longer ones and made the droop on that 1 corner wayyy too long. Not sure how I missed that one. Main handling issue seems to be understeer at medium and high speeds but I should be able to dial that out.

The car is a fun exercise right now in weight transfer though.

Have acquired a few more projects and parts. Bought 2 LXTs and a pile of parts to add to my other LXT(on a jrx2 chassis that i'm swapping out) and piles of JRX2 parts that I bought back in the 90s. Plan is to make a JRX2 and a JRX Pro SE as well. these will be longer term projects though, mostly to keep myself from draining my bank accounts

[RogueIV]

got my order of JRX2 wheels from JC Racing (and a set of spoked XX-4 wheels) and decided to mount up the tires. Really liking the look. Really need my new body now.

[RogueIV]

Got my MCI and TBG order in a few days ago and decided to paint up and decal the Pro finally.







It wasn't my intention to do Gulf colors but the colors just go so well.

Even did my Mini JRX2 in the same scheme, now if they only made neon orange wheels for the mini.

[Frankentruck]

They make an awesome looking pair of buggies!

[RogueIV]

Going through some stuff i realized I had an extra set of truck threaded shock bodies. The shocks on this car weren't a matching set and on top of that the silver front bodies don't seem to seal up to the newer style of cartridges very well. I needed an excuse to use my new ultrasonic cleaner so I cleaned and filled up the shock bodies and put them on the car and also went a little stiffer with some red front springs instead of the pinks. The Futaba esc is going into a different car so I put a Novak in this one. Orange is kind of a theme with this chassis so it does match up pretty well. Might bring it to the track tomorrow and run a few laps with it. Also need to find a better place to take pictures of it.